This study involves the development, implementation, and evaluation of a culturally appropriate, HIV-prevention intervention aimed at 6th and 7th grade children with special emphasis on Hispanics. The overall goal of the intervention is to reduce the risk of HIV infection, other STDs and pregnancy among preadolescents, by increasing the proportion who postpone sexual involvement and the proportion who use condoms among those who are sexually active. The intervention will be designed to improve preadolescents' decision- making, refusal and communication skills; to establish and reinforce preadolescents' norms about delaying sexual intercourse and using condoms; and to increase the frequency of preadolescents' communication about sexually-related topics with their parents and other resource adults. The intervention will rely on social learning theory and promotion of self-regulation of behavior. The intervention involves an educational curriculum developed specifically for 6th and 7th grade classrooms with special emphasis on Hispanics and based upon the only curriculum clearly demonstrated to be effective, Reducing the Risk. The intervention will be provided by a specially-trained school-based family life educator. Activities will be developed and pretested in the first 18 months of the project. Implementation and evaluation of the intervention will occur in the last three and a half years of the project. Twenty middle schools with high proportions of Hispanic students will be randomly assigned to the treatment and control groups. One cohort of sixth graders will be followed for 30 months. Multi-level analysis will be conducted, including both student-level and school-level data to account for clustering in the experimental design. Analyses will identify differences in the proportion of preadolescents in each group who have had sexual intercourse in 8th grade and the proportion of sexually active preadolescents consistently using condoms. Analyses will also provide information about whether program impact is similar for Hispanic and non-Hispanic students and for males and females; will assess the relative impact of the curriculum upon student mediating or impact variables (e.g., perceived self-efficacy); and will identify which of these impact or mediating variables are most highly associated with positive behavioral outcomes for Hispanics and non-Hispanics and for boys and girls.